1. Field of the Invention
This invention relates to a granulating-coating apparatus capable of removing adhered articles such as a bonding agent or a coating liquid which adhere to spray guns, i.e., spray guns formed in a spraying means, and relates to a method of granulating and coating by use of the apparatus.
2. Related Art Statement
As an apparatus for granulating or coating pharmaceuticals and foodstuffs, there has been widely known such an apparatus that articles to be processed (herein after simply referred to as "articles") such as tablets, granules or nuts are contained in a processing container as a rotary drum being rotated about a substantially horizontal rotary axis to form an accumulated layer on the articles, and liquid such as a binder liquid or a coating liquid is sprayed from spray guns to the articles, and then gas is caused to flow through the accumulated layer on the articles, so that granulating and coating can be performed. In the apparatus as described above, such a disadvantage is presented that a part of the binder liquid or the coating liquid is dried and solidified in the vicinity of the forward ends of the spray guns, and peeled off and dropped into the processing container, to thereby contaminate the articles and deteriorate the quality of the articles. This disadvantage is particularly notable in the case where sugar coating, chocolate coating and so forth are performed.
Furthermore, in the case of a fluidized bed granulating-coating apparatus, in which air is caused to flow from under the articles, in addition to the above-described disadvantage, such a disadvantage is presented that fine particles accompanied with fluidized air adhere to the spray guns.
In order to obviate the disadvantage of the adhesion of the coating liquid or the binder liquid to the spray guns as described above, various techniques have heretofore been proposed.
For example, Japanese Patent Laid-Open No. 62-11576 discloses a movable and elastic partition walls provided in the vicinity of forward ends of spray guns and distortion is given to the partition walls, to thereby peel off the adhered articles. Furthermore, in Japanese Patent Laid-Open No. 62-155956, a guide is detachably provided in a manner to cover a side surface of a forward end portion of a spray gun, an extensible diaphragm is mounted in a manner to cover a nozzle formed in the spray gun, and air is supplied to the diaphragm to expand it, to thereby remove the adhered articles. However, in these apparatuses, although the adhered articles such as the coating liquid or the binder liquid, which adhere to the nozzles and thereabout, can be removed only partially, it is difficult to completely remove the adhered articles on the nozzles themselves because the apparatus is of deforming elastic members around the nozzles such as the partition walls and the diaphragm. And, it is not desirable that the adhered articles, which have been removed, are dropped to contaminate the articles. Further, because the elastic members are deformed, the durability of the apparatus itself is not satisfactory.
Furthermore, in Japanese Patent Laid-Open No. 60-241956, there is proposed an apparatus in which a scratching blade is rotatably mounted on an outer periphery and an end surface of an outer tubular portion which is covering outer peripheries of ends of nozzles formed in spray guns. However, in this apparatus, the coating liquid or the binder liquid adheres to the scratching blade, and there is presented the disadvantage similar to the case where the coating liquid or the binder liquid adheres to the spray guns.
In Japanese Patent Laid-Open No. 60-501148, there is proposed that spray guns are provided in a manner to be movable between a spraying position and a cleaning position and then these spray guns are cleaned by cleaning liquid stored in a shielding means provided on rotating axis in a pan. However, in this apparatus, there are presented such a disadvantage that the mechanism is complicated so as to have the space within the pan narrowed, and another disadvantage that the shielding means itself is stained with the adhered articles.
In Japanese Patent Laid-Open No. 2-233164, there is proposed an apparatus comprising a case; spray guns housed in said case, said spray guns being arranged to be movable between a spraying position and a cleaning position; and a solution tank provided in said case which stores a cleaning solution, in which the spray guns are immersed in said cleaning solution to be cleaned. However, in this apparatus also, there is presented the disadvantage similar to the apparatus described in Japanese Patent Laid-Open No. 60-501148.